This allegory ends the part of Ecclesiastes that actually was written or compiled by the Preacher himself. Many commentators have read it as a description of the way the body starts to decay and shutdown when old age arrives. Although parts of the passage don't seem to exactly fit with this interpretation, it's still ancient enough and important enough for us to talk about it.
Interestingly, the allegory (if it is an allegory) compares the death of the human body with the end of the world, itself. It begins with the light from the sun, moon, and stars growing dim—which could be a symbol for the life-force that powers the body growing weaker and weaker. The guardians who guard the house start to tremble—meaning that the defenses that have kept the body working start to weaken. The strong men grow weak, the women who used to grind at the mills stop grinding—which could be metaphors for how the body can't do the work it needs to do anymore (can't digest, can't keep pumping blood, can't breathe, etc.).
Code Name: Maids and Guardians
Traditionally, commentators in the Jewish Talmud got really specific: they said that the maids who were grinding were the teeth, and the guardians who were guarding the house were the arms, and that the strong men were the legs. When the women who look out of the windows start to turn away, that's eyesight beginning to fail.
While the almond tree will keep blooming, and the world of nature will be renewed with spring, human beings won't. They're all condemned to die, just like a silver cord will eventually be forced to snap and a golden bowl will break.
Yet, despite all this, there's one thing Ecclesiastes eagerly reminds his readers to do: remember their Creator, especially when they're still young and have their health. This is really his last word:
Remember your creator […] before the silver cord is snapped, and the golden bowl is broken, and the pitcher is broken at the fountain, and the wheel broken at the cistern, and the dust returns to the earth as it was, and the breath returns to God who gave it. Vanity of vanities, says the Teacher; all is vanity. (NRSV 12:1-8)